Marine vessels, including ships and barges, are used to transport large cargo loads by water routes. By way of example, deck barges are designed to transport cargo situated on the deck of the barge, while tank barges are designed to transport liquid cargo, such as oil, stored in holding tanks inside the barge's hull. Another common type of barge is the bulk or hopper barge, characterized by compartments between the fore and aft bulkheads of the barge for storing bulk materials and items such as rock, coal, sand, soil, steel, grain, and garbage.
Heretofore, barges have been constructed by providing a plurality of transverse truss assemblies spaced at intervals along the longitudinal extent of the barge, and attaching a shell to the respective undersides of the truss assemblies and a deck to the respective topsides of the truss assemblies. Each truss assembly typically includes a lower C-channel member and a parallel upper C-channel member connected by vertical and diagonal truss members. The shell, which may be a plurality of steel plates arranged side-to-side and end-to-end to cover a specified area, is attached to the lower channel member of each truss assembly by way of a series of longitudinally extending angle members spaced at transverse intervals. The deck, like the shell, may be a plurality of steel plates attached in a similar fashion to the upper channel member of each truss assembly by way of a series of longitudinally extending angle members spaced at transverse intervals. A second (inner) shell may be provided by arranging steel plates between the lower channel members of the truss assemblies and the longitudinal angle members to which the first (outer) shell is fixed.
FIGS. 1A and 1B illustrate a common construction of a single shelled barge in accordance with prior art technology. The longitudinal axis of the barge runs into and out of the drawing page. A transverse truss assembly 10 includes a lower C-channel member 12 and an upper C-channel member 14 connected by vertical truss members 16 and diagonal truss members 18. The truss members 16, 18 may be lengths of structural steel angle on channel welded at their respective end regions to the outer web surfaces of channel members 12, 14. Longitudinal angle members 22 may be spaced at transverse intervals, as shown in FIG. 1A. The flange of each angle member 22 may be welded to a bottom flange of lower channel member 12, and the web of each angle member 22 may be welded to an adjacent plate forming part of an outer shell 24.
Further longitudinal angle members 26 may have their respective flanges welded to upper channel member 14 and their respective webs welded to plates forming a deck 28.
As may be understood, prior art construction as described above utilizes structural steel members having standard cross-sectional configurations in conjunction with steel plate. While this may simplify purchasing of structural steel angle, channel and plate, it complicates fabrication and assembly. For example, multiple longitudinal weld seams are needed to fix the web of longitudinal angle members 22, 26 to an adjacent plate of the outer shell 24 or deck 28, as the case may be. The angle members 22, 26 must be properly positioned with respect to the plate prior to welding, which requires additional man-hours and fixtures for set-up.